Many studies have analyzed outcomes following salvage radiation therapy (RT) after biochemical recurrence--defined as the presence of detectable serum prostate-specific antigen (PSA)--following radical prostatectomy (RP). However, the management of patients with detectable PSA following RP, which is not specific for tumor recurrence, is a matter of debate. This study aimed to evaluate oncological results of three-dimensional conformal RT (3D-CRT) in patients who had biochemical recurrence.
The study included patients who underwent RP, who had a postoperative PSA level--determined between 2 and 4 months after surgery--that was greater than 0.1 ng/ml, and who subsequently received monotherapy with 3D-CRT on the prostate bed. The patients' clinical, characteristics and the pathological characteristics of their biopsy specimens were recorded. The main endpoint was biochemical failure after 3D-CRT, defined as three consecutive elevated PSA levels.
The tumors in the 46 patients included 4 (9%) pT2a, 7 (15%) pT2b, 14 (30%) pT2c, 10 (22%) pT3a, 10 (22%) pT3b, and 1 (2%) pT4 tumor. The Gleason score was 7 or higher in 37 patients (80%). Positive surgical margins were seen in 37 patients (80%). The patients had a median postoperative PSA level of 0.29 ng/ml (range, 0.1-5.8 ng/ml) and a median PSA doubling time (PSADT) before RT of 6 months (range, 1-53 months). The rate of biochemical recurrence free survival after 3D-RT was 66% at 30 months. Preoperative PSA, PSADT before RT, and D'Amico scores were significantly associated with biochemical failure after 3D-CRT (p < 0.05).
In cases of persistent PSA following RP for prostate cancer, 3D-CRT can be used as monotherapy with a significant chance of recurrence free survival. Preoperative PSA, PSADT before RT, and D'Amico score are predictive factors of recurrence following RT.